Clasp for removable false teeth



1962 KANSUKE YAMAMOTO 3,047,952

CLA SP FOR REMOVABLE FALSE TEETH Filed June 25, 1959 mm-WAN 3,047,952CLASP FGR REMGVABLE FALE TEETH Kansuke Yamamoto, 4589 ll-chonieHigashhtlltuho, Shinjuku-ku, Tokyo, .lapan Filed June 25, 1959, Ser. No.822,861 2 Claims. (Cl. 32--5) The present invention relates to claspswhich can be used for an extended period of time for removable falseteeth without loss of spring power.

Hitherto, clasps for false teeth have been formed with a claspingportion on either end thereof for clasping basic supporting teeth, andfurther formed with a supporting portion connecting together saidclasping portions. Since said supporting portion is inserted deep intothe false tooth base, the elasticity of clasping portion is greatlyrestricted, thus preventing said clasping portion from developmg asufficient spring action. Accordingly, on the inserting or withdrawingthe false teeth, the clasping portron does not usually open suificientlyunder pressure to meet protruding portions of the basic supporting toothwhen said clasping portion passes over said protruded portion. As a.result, insertion or removal of false teeth cannot be effected smoothly,and consequently no close contact can be provided between the false andthe basic supporting teeth. Moreover, when the retaining force of theclasping portion is insufficient, the loosening and even the eventualloss of the. basic supporting teeth are likely to occur. As a result, animproper chewing pressure occurs on the basic supporting tooth,resulting in a torsional strain due to lever action of such pressure.Therefore, disadvantages result which make the usual dentists claspundesirable. Such clasps are easily damaged due to strains upon them,and do not possess sufficient durability.

In order to remove these disadvantages, the clasp according to theinvention is formed of an alloy wire having high strength and toughnesswhich is bent into approximately V-shape to form a supporting wireportion. Both ends of said wire are symmetrically made arcuate to form aclasping portion for clasping a basic supporting tooth. The V-shapedportion of the supporting wire is covered with a wrapping tube made ofan alloy having high toughness and also formed in V-shape, and is of adiameter to leave a clearance between the inner surface of said wrappingtube and the outer surface of the supporting wire. This clearance isfilled with a soft plastic substance to afford a resilient connectionbetween the wire and the tube. The tube is then fixed within the falsetooth base. According to the invention, therefore, the supporting Wireportion is not stationary, but movable with respect to the false toothbase. The clasping portion is advantageously capable of retaining asubstantially uniform pressure against the false tooth base.

The invention will now be explained in further detail with reference tothe accompanying drawings, in which,

FIG. 1 is a plan view of the clasp according to the present invention;

FIG. 2 is a front view thereof;

FIG. 3 is a horizontal sectional View of FIG. 1 on an enlarged scale;

FIG. 4 is a front view of the clasp according to this invention, as itis used; and

FIG. 5 is a plan view thereof.

Referring to the accompanying drawings, there is shown a wire A, whichis made of an alloy. The wire A has a supporting wire portion 1 formedin approximately V- shape, and also has clasping portions 2 at the endsof the V-shaped portion 1, symmetrically bent to engage a basicsupporting tooth 7.

A wrapping tube 3 is made of an alloy similar to that of the wire A,covering said supporting wire portion 1 and forming a V-shapeconfiguration like that of the wire portion 11. Thus, the wrapping tube3 surrounds the V-shaped supporting portion 1 of the wire A being at allpoints coaxial therewith. The wrapping tube 3 has a slightly largerinner diameter than that of the supporting wire portion 1, leaving aclearance between the supporting wire portion 1 and the inner Wallsurface of the wrapping tube 3. A soft plastic body 5 fills theclearance 4. The wrapping tube 3 is embedded in a false tooth base 6,and is secured thereto.

Thus, it is apparent from the foregoing description, that, since theouter surface of the wrapping tube 3 is en bedded in the false toothbase 6, the clasping portion 2 of the wire A has limited resilientmovability with respect to the false tooth base s together with thesupporting wire portion 1. Because, by virtue of the soft plastic filler5 in the clearance 4-, a cushioning eifect is obtained which givesmobile properties to the wire A. Thus the supporting wire portion Itbecomes somewhat movable with respect to the false tooth base 6, even ifthe wrapping tube 3 is embedded in the false tooth base 6 and securedthereto, in a local false tooth construction. According to theinvention, the following advantages are attainable:

(l) A satisfactory balance in the pressure exerted on a supporting tooth7 and other portions can be obtained; a

yielding retaining action can be developed similar to the resilientaction of parts of the human body, and a like movement of the denturecan be induced; and the support ing force can be stabilized withoutimparting any undue pressure on the supporting tooth.

(2) The supporting wire portion 1 attains a cushioned behavior by virtueof the soft plastic filler 5 filling the space 4 between the wire 1 andthe wrapping tube E; and the clasping portion 2 makes possible a freeopening of the portion 1 under pressure and free clipping action, aboutthe supporting teeth thus making possible a smooth and accurate fittingof the four ends of the claspin portions 2 about the contractions of thetwo supporting teeth '7. See FIGS. 4 and 5. Consequently the claspingportions 2 grasp the narrowest portion of the neck of the supportingteeth, hold a configuratory balance and obtain stability of the teeth.

(3) Undue stress occurs seldom on the wire A, because the supportingwire portion 1 has no fixed points against the false tooth base 6.Therefore, finer wires can be utilized, because the fatigue,deformation, rupture, etc. are all low. As a result, it becomes possibleto develop a spring action effectively. The feeling of having a aiiensubstance in the mouth, due to the clasp used, is very faint. Also theesthetic sense in connection with having a foreign body in the mouth canalso be kept substantially high. Further, a whole supporting device canbe made simple and highly durable.

(4) A uniform cushioning layer is formed overv each outer face of thesupporting wire 1 and also the inner wall of wrapping tube 3respectively, by the soft plastic filler 5 filling the clearance 4Within the wrapping tube 3. The operation of clasping portion 2 isperformed more uniformly and more smoothly by the cushioning layer toobtain a resilient adjustment. Thus the supporting teeth 7 may always beoperated independently in their natural movement, without beingsubjected to the effect by impact, excess pressure, tortional stress, orotherwise imparted unexpectedly to the supporting teeth '7 by the falseteeth, thus making it possible to chew with the supporting teeth withoutloosening them.

(5) Foreign matter is prevented by soft plastic filler 5 from enteringinto the clearance 4. Thus, the clasp is advantageous from the hygienicpoint of view, and at the same time the rust proofing is effected, aswell as prevention of breakage of the wrapping tube 3 are attained foran extended period of time.

What I claim is:

l. A clasp for attaching removable false teeth to a basic supportingtooth, said clasp comprising a wire having a V-shaped supporting portionand clasping portions at the ends of the V-shaped portion symmetricallybent to engage between them a basic supporting tooth, said V-shapedportion and said clasping portion being inclined toward each other at anobtuse angle, a wrapping tube surrounding the ii-shaped supportingportion of said wire at all points coaxial therewith, said wrapping tubehaving a slightly larger inner diameter than that of said wire leaving aclearance space of constant dimension between the supporting portion ofsaid wire and the inner wall surface of said wrapping tube, and a softplastic body filling the space between said wrapping tube and thesupporting portion of said wire to provide a cushioning effect betweensaid wire and said wrapping tube, said wrapping tube being adapted to beembedded in a false tooth base and fixed thereto, whereby the claspingportions of said who have limited resilient movability with respect tothe false tooth base.

2. In a device for attaching one or more false teeth between two spacedbasic supporting teeth, the combinanation comprising a false tooth baseto which such teeth are attached, two wires each having a V-shapedsupporting portion and clasping portions at the ends of the V- A shapedportion symmetrically bent to engage between them a basic supportingtooth, each V-shaped portion and its corresponding clasping portionsbeing inclined with re spect to each other and defining an obtuse angletherebetween, a wrapping tube surrounding the if-shaped portion of eachof said wires at all points coaxial therewith, each of said wrappingtubes having a slightly larger diameter than that of the V-shapedportion which it surrounds leaving a clearance space of constantdimension between the supporting portion of the corresponding wire andthe inner wall surface of said wrapping tube, and a soft plastic bodyfilling the space between each wrapping tube and the supporting portionof the corresponding wire to provide a cushioning eifect between each ofsaid wires and the corresponding wrapping tube, said wrapping tubesbeing substantially oppositely embedded in and fixed to said false toothbase with the clasping portions of said wire extending outwardlytherefrom, whereby the clasping portions, of each of said Wires areadapted to engage one of said spaced basic supporting teeth and saidfalse tooth base has limited resilient mobility with respect to theclasps engaging the spaced basic supporting teeth.

References Cited in the file of this patent UNITED STATES PATENTS2,483,353 Seveilhac et al. Sept. 27, 1949

